Are all the ground pins on the 6551 tied internally together or is each dependent on its respective DIO pin? In other words would it be ok to ground just one gnd pin from the 6551 to a DUT and use multiple DIO signals?
The ground pins on 6551 are internally tied together. You can test it by just connecting a DMM across two ground pins and perform continuity test on it.
Kalyan
Kalyanramu Vemishetty Automated Test Systems Engineer National Instruments
